Gas discharge display apparatus

ABSTRACT

A gas discharge display panel comprises a gas discharge shifting register for propagating glow discharges from stage to stage thereof in response to shifting signals. The apparatus includes a plurality of gas discharge display cells and electrode means interposed between the shifting register and the display cells and having a plurality of gas conductive channels therethrough extending from the stages of the shifting register to the display cells. The electrode means is selectively connectible to a source of addressing potentials generated in timed relation with respect to the shifting signals whereby gas discharge columns are selectively extended in the channels from the glowing stages of the shifting register to the display cells thereby igniting gas discharges in selected display cells.

[ Dec. 25, 1973 Primary Examiner-Roy Lake Assistant Examiner- Lawrence 1.,Dahl Attorney-S. C. Yeaton [57] ABSTRACT A gas discharge display panel comprises a gas discharge shifting register for propagating glow discharges from stage to stage thereof in response to shifting signals. The apparatus includes a plurality of gas discharge display cells and electrode means interposed between the shifting register and the display cells and having a plurality of gas conductive channels therethrough extending from the stages of the shifting register to the display cells. The electrode means is selectively connectible to a source of addressing potentials generated in timed relation with respect to the y gas discharge columns are se- H05b 37/00 315/169 R, 169 TV b en.m m n hwum w.m S

mwm nX .m gw y n 6 S ft gfl m oma Si St c XVVXXX RVR Inventor: Theodore H. Bonn, Newton Centre,

Mass.

[73] Assignee: Sperry Rand Corporation, New

York, NY.

July 12, 1971 [21] App]. No.: 161,584

315/169 TV, 315/169 R References Cited UNITED STATES PATENTS United States Patent [191 Bonn GAS DISCHARGE DISPLAY APPARATUS I [22 Filed:

[51 Int.

[58] Field of Search........

the channels from the glowing g register to the display cells igniting gas discharges in selected display L'Heureux...................... Kupsky.......... Caras.........

Kupsky Kupsky.............. Veron et al.

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sum 13 HF 13 ADD RESS I we CIRCUITS IN VE/VTOR D1500 ORE h. Bmv/v ATTORNEY GAS DISCHARGE DISPLAY APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention pertains to gasdischarge display panel apparatus particularly' of the selectively lit dot variety including improved means for glow selection.

2. Description of thePrior Art Gas discharge display panels are known in the prior art that utilize dot-matrix display formats for the visual presentation of information. -A dot-matrix display panel is defined as apparatus incorporating a matrix of points which may be selectively lit to display patterns of information. Such a dot-matrix display is described in US.

Pat. application S.N. 90,538 filed Nov. 18, 1970, in the names of ClaudeD.,I .'ustig and Albert W. Baird III, entitled Digitally Addressable Gas Discharge Display Apparatus and assigned to the assignee of the present invention. Briefly, the device described in said Ser. No. 90,538 comprises a reservoir of ionizable gas and a plurality of gas discharge display cells. The device includes a plurality of addressing electrodes each having a plurality of apertures therethrough. The addressing electrodes are arranged in stacked configuration so that the apertures align to form gas conductive channels extending from the reservoir to the display cells, respectively. The addressing electrodes are selectively connectible to sources of electrical potential whereby gas discharge columns are extended from the reservoir through selected channels igniting gas discharges in selected display cells.

Although such a display device is suitable for most purposes, limitations arise in applications requiring very large numbers of display'points. Such large scale displays may find usage in air trafi'ic control situations; at airports to display flight information such as arrivals, departures and loadinggates; in stock market displays; outdoors to display traffic controllinformation and in programmable commercial advertising signs as well as others. The display of said Ser. 'No. 90,538 may not be suited to such large scale applications since the reservoir of ionized gas mustv extend over the entire matrix of display points and the gas'therein maintained uniformly ionized over the entire area .of the reservoir. Such an ionized gas reservoir. may be exceedingly difficult and hence expensive to manufacture and may require prohibitively largequantities of electrical power.

Additionally, large'numbers of stacked and aligned addressing electrodes mayrbe required further complicating constructional procedures and and increasing manufacturing costs.

The afore-described display devices utilize d.c. or pulsed d.c. voltages for the ionization, sustainingand addressing potentials. The advantages of using d.c. ex-

citation compared to a.c. excitation are discussed in said Ser. No. 90,538. Prior art a.c. display panels are known that comprise a plurality of three-phase shifting registers for shifting in patterns of binary information.

A plurality of shifting electrodes are arranged along the lengths of the registers external to the gas-tight envelope of the device. The electrodes are interconnected in a conventional staggered three-phase shifting arrangement where every third electrode defines a stage of the register and the two adjacent electrodes intermediate every third electrode are utilized as guide electrodes for transferring the glow from one stage to the next. The prior art devices further include a plurality of display cells comprising orthogonally disposed strips of conductors and insulators arranged in egg-crate configuration. The display cells are separated from the shifting registers by an insulating plate having a plurality of apertures therethrough, every third shifting electrode defining a stage of a shifting register communieating with a display cell through an aperture, respectively. Electrical leads disposed in the apertures provide transferrance of a glow pattern from the shifting registers to the display cells after the pattern has been shifted into the register.

Since these prior art display devices operate with a.c. excitation, they exhibit disadvantages with respect to apparatus of the type of the present invention that operate with d.c. excitation. For example, circuits required to switch a.c. potentials are normally more complex than those utilized to switch d.c. voltages. Gas discharge a.c. panels are known to radiate objectionable radio frequency interference. D.C. panels are, of course, not subject to this limitation. Because of the capacitive coupling of the shifting electrodes with respect to the shifting registers, glow propagation along the registers is significantly slower in a.c. devices than in d.c. devices because glow tum-off at the stages of the registers in the a.c. devices requires discharge of the capacitors formed by the electrodes of the register and the intermediate insulating walls thereof.

The prior art a.c. display panels described suffer from the further disadvantages which are overcome by the present invention. For example, a large scale prior art display panel requires exceedingly large capacity switching circuits for operating the shifting registers since large numbers of glow discharges must be simultaneously shifted dependent upon the instantaneous pattern of information in the registers. Similarly, a high power pulse is required to transfer these large numbers of glow discharges from the stages of the registers to the display cells. Should these prior art devices attempt to conserve electrical power by shifting the glow discharges into position and transferring them to the display cells one information bit at a time, exceedingly slow operation would result.

In addition, the prior art displays described above tend to be slower in operation than certain of the embodiments of the present invention since glow information is serially shifted into the prior art displays one bit at a time whereas in the certain embodiments of the present invention, pluralities of glow points are simultaneously shifted in a manner to be clarified in the description of the invention to follow.

SUMMARY OF THE INVENTION The present invention overcomes the disadvantages of the prior art discussed with respect to said Ser. No. 90,538 while retaining the advantages thereof. The invention further overcomes the disadvantages discussed with respect to the prior art display panels of the a.c. variety. The present invention overcomes these disadvantages by providing a gas discharge shifting register for propagating glow discharges from stage to stage to the register shifting signals whereby gas discharge columns are selectively extended in the channels from the glowing stages of the register'to the display cells thereby igniting gas discharges in selected display cells. The arrangement of the present invention overcomes the disadvantages of the prior art in a manner to be clarified in the descriptions to follow and in the illustrations of the embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1a and lb are exploded perspective views of one of the preferred embodiments of the invention.

FIG. 2 is a voltage waveform diagram useful in explaining the operation of the embodiments of the invention.

FIGS. 3a-3e are exploded perspective views of another preferred embodiment of the invention.

FIGS. 4a-4c is a detailed exploded perspective view of a portion of the display of FIG. 3.

FIGS. 5a and 5b are exploded perspective views of still another preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a gas discharge display device 10, in accordance with one of the preferred embodiments of the invention, is illustrated. The display device comprises a gas discharge shifting register 11, a stack, i.e., superposed arrangement, of addressing anode electrodes 12 and a plurality of gas discharge display memory cells 13, the shifting register 11, the addressing anode stack 12 and the display memory cells 13 being in superposed arrangement with respect to each other.

It will be understood in the descriptions following that the electrically conductive members of the display 10 are comprised of any suitable metal and that the electrically isolating members thereof are comprised of any suitable insulating material. A suitable choice of materials may, for example, be nickel-iron alloy (51% nickel and 49% iron) of a type in wide spread commercial usage in electron tube devices, and soda-lime glass, respectively. The coefficients of thermal expansion of these materials are substantially identical providing manufacturing advantages well appreciated in the art.

It is further understood that the display device 10 is adapted to be filled by any convenient means (not shown) with a suitable ionizable gas such as, for example, Penning mixture (99.5% neon and 0.5% argon).

The shifting register 11 is comprised of a plurality of cathode electrodes 14, 15, 16, 17, 18, 19, 20, 21 and 22 and an anode electrode plate 26 spaced from the cathodes 14-22. A plurality of apertures are disposed through the anode plate 26 forming a matrix configuration, for example the 8 X 8 matrix of 64 apertures depicted for purposes of illustration. The plurality of cathodes 14-22 are separated from each other by a plurality of electrically insulating baffle plates 27, 28, 29, 30, 31, 32, 33 and 34, respectively. The baffle plates 27-34 may, for convenience, be integrally formed with an electrically insulating back plate and wall structure 38 which may form part of the gastight envelope of the display device 10. Electrical connections are made to the cathodes 14-22 via electrically conductive pins 39, 40,41, 42, 43, 44, 45, 46 and 47, respectively, which protrude from the rear of the structure 38 .through conventional gastight seals (not shown).

The cathodes 14-22 and the anode plate 26 together with the baffle plates 27-34 and the side wall members of the structure 38, cooperate to form the stages of the shifting register 11. For example, the register 11 includes a starter stage 50 which is comprised of the cathode 14, the adjacent columnar section of the anode plate 26, the baffle plate 27 and the associated side wall of the structure 38. Similarly, the register 11 includes a first information stage 51 which is comprised of the cathode 15, the associated columnar section of the anode 26 and the baffle plates 27 and 28. In a similar manner, the register 11 includes second through eighth information stages 52, 53, 54, 55, 56, 57 and 58, respectively. The stages 52-58 are similarly defined by the cathodes 16-22, the associated columnar sections of the anode plate 26 and the adjacent paired bafile plates 28-34 respectively. It is appreciated that each of the stages 50-58 comprises a gas discharge register cell for supporting a glow discharge at the respective cathode electrode thereof.

The baffle plates 27-34 disposed between the stages 50-58, respectively, are so constructed and arranged that gas plasma propagates freely from each stage to the next following stage and is impeded from propagating freely further to the stage following the next following stage. This result is achieved by openings 60, 61, 62, 63, 64, 65, 66 and 67 through the respective baffle plates 27-34 connecting the adjacent stages of the register 1 1, respectively. The opening 60 connects one end of the stages 50 and 51 while the opening 61 connects the opposite end of the stages 51 and 52. In a similar manner, the opening 62 connects the one end of the stages 52 and 53 while the opening 63 connects the opposite end of the stages 53 and 54. In a like manner, the openings 64-67 are disposed in staggered arrangement with respect to the ends of the register cells that they connect respectively. It is therefore appreciated that plasma from a glowing register stage, for example the stage 50, may propagate freely through the opening 60 to the stage 51 but is impeded from propagating to the higher numbered stages because of the serpentine path provided by the arrangement of the openings 60-67. It will be appreciated that openings of a variety of shapes may be utilized. For example, holes or notches may be employed dependent on the constructional characteristics desired.

As previously discussed, electrical connections are made to the cathodes 14-22 via the pins 39-47, respectively. The pin 39 is connected to a source of shifting signals via a lead 71. The pins 40, 43 and 46 are connected together and to the source of shifting signals 70 via a lead 72. In a similar manner, the pins 41, 44 and 47 are connected to the source of shifting signals 70 by a lead 73 and in a like manner, the pins 42 and 45 are connected to the source of shifting signals 70 via a lead 74. The voltages provided by the source of shifting signals 70 are applied between the respective cathodes 14-22 and the anode 26 by means of the cathode leads 71-74 and an anode lead 75 connected to the anode plate 26 through a discharge stabilizing resistor 76. For reference, the anode 26 is connected, for example, to ground potential.

Referring now to FIG. 2, the voltage waveforms applied by the source of shifting signals 70 to the leads 71-74, respectively, are illustrated and are designated by the numbers of the respective leads on which they appear. The lead 71 voltage is applied between the cathode 14 of the starter stage 50 and the anode 26. This voltage is chosen of magnitude equal to the ionization potential of the gas. Thus, whenever a lead 71 voltage pulse is applied to the cathode 14, a glow discharge is initiated in the starter stage 50 of the'shifting register 11. The leads 72-74 voltages are chosen of magnitude equal to the sustaining potential of the gas. These voltages applied to the respective stages of the register 11 are of insufficient magnitude to cause a gas discharge in the absence of gas plasma from an adjacent stage but will ignite and sustain a discharge at a stage when plasma from an adjacent stage is present. In a manner to be described hereinafter, the lead 71 voltage initiates a glow discharge in the stage 50 of the register 11 and the leads 72-74 voltages tranfer the glow from stage to stage thereof. It is appreciated that the leads 71-74 voltages are conventional in nature and may be provided by conventionally designed circuits of types well known to practitioners in the art.

Referring again to FIG. 1, the stack of addressing anodes 12 is disposed adjacent the shifting register 11. The stack of addressing anodes 12 is comprised of anode plates 80, 81 and 82, each of which has a plurality of apertures therethrough forming a matrix configuration aligned with the apertures through the plate 26. Interposed between the addressing anodes 80-82 are electrical insulators 83 and 84, respectively, each having a matrix of apertures therethrough aligned with the apertures through the addressing anodes 80-82. Additionally, an apertured insulating plate 85 is interposed between the register anode 26 and the addressing electrode 80.

Each of the addressing anodes 80-82 is comprised of two electrically conductive portions, electrically isolated from each other, one-half of the apertures being disposed through each of the portions respectively. The addressing anode 80 is comprised of portions 86 and 87, the portion 86 containing one-half of the adjacent rows of the matrix of apertures and the portion 87 containing the other half thereof. The addressing anode 81 is comprised of portions 88 and 89, the portion 88 containing one-half of the alternate pairs of adjacent rows of the matrix of apertures and the portion 89 containing the other half thereof. The addressing anode 82 is comprised of the portions 90 and 91, the portion 90 containing one-half of the alternate rows of the matrix of apertures and the portion 91 containing the other half thereof.

The portions 86-91 are connected to addressing circuits 95 through leads 96-101, respectively. The addressing circuits 95 comprise conventional circuits for selectively applying either a positive or negative potential to each of the leads 96-101 in a manner and for reasons to be discussed.

The plurality of gas discharge memory cells13 are comprised of a cathode plate 105, an electrically insulating plate 106 and a transparent metal anode film 107 disposed on the surface 108 of a transparent insulating cover plate 109. The plates 105 and 106 each have a matrix of apertures therethrough in a manner similar to that described with respect to the plate 26 and aligned therewith. The anode film 107 comprises any suitable transparent metal film such as tin oxide deposited on the surface 108 of the plate 109. Additionally, an apertured insulating plate 1 is interposed between the addressing anode 82 and the cathode plate 105. It is understood that the plurality of apertures in the cathode plate and the corresponding plurality of apertures in the insulating plate 106 in combination with the anode film 107 form the plurality of gas discharge display memory cells 13.

It is appreciated that alternatively a fine metal mesh may be utilized instead of the anode film 107. A further alternative design is to utilize an apertured metal anode plate instead of the transparent plate 109 and the anode film 107, this apertured plate being suitably sealed to retain the ionizable gas.

A suitable source 111 of gas discharge sustaining potential selectable connected across the cathode 105 and the anode 107 for reasons to be explained. The cathode 105 is also connected through a suitably largevalued isolating resistor .112 to the anode 26 at the ground connection thereof for reasons to be later discussed.

It should be appreciated that the cathode 105 may be utilized as an anode and the anode 107 utilized as a cathode by reversing the polarity of the source 111 and incorporating a suitable construction for the electrode 107.

It is now appreciated that the anode plate 26, the addressing electrode plates 80-82, the insulating plates 83-85 as well as the insulating plates 106 and and the cathode plate 105, are stacked with respect to each other so that the respective matrices of apertures therethrough align to form a matrix of gas conductive channels extending from the stages 51-58 of the shifting register 11 to the plurality of gas discharge display memory cells 13, the channels comprising each column of the matrix connecting with a respective stage of the register 11.

It is further appreciated that the member 38 and the plate members 26, 80-85, 105, 106, 109 and 110 are contiguously stacked and sealed at the edges thereof by any convenient means (not shown) to fonn a gas-tight structure. Alternatively, the plate members forming the display 10, may be mounted inside a gastight envelope (not shown) with electrical connections made through gastight seals in the envelope.

The operating principles of the display device 10 will now be explained with respect to FIGS. 1 and 2. During time interval 1 17 (FIG. 2) the voltage source 70 applies the lead 71 ionizing pulse to the cathode 14 thus causing a glow discharge over the surface area thereof. it is noted that in the time interval 117, gas discharge sustaining potentials are applied to the cathodes 15 and 17 via the leads 72 and 74 voltages, respectively, and ground potential is applied to the cathode 16 via the lead 73 voltage. Gas plasma from the glowing starter stage 50 propagates through the opening 60 igniting a glow discharge in the stage 51. The gas plasma is impeded from propagating to the stage 52 firstly by the barrier 28 and secondly by the ground potential applied to the cathode 16. The cathode 17 and the several higher numbered cathodes which have sustaining potential applied thereto during the time interval 117 will not ignite because gas plasma cannot propagate thereto from the glowing stage 50 through the serpentine path provided by the barriers 27-34.

During time interval 118, following the time interval 117, the lead 71 voltage returns to ground potential thereby extinguishing the glow discharge at the starter stage 50. In the time interval 1 18 the lead 72 sustaining potential maintains the glow discharge in the stage 51 and selected display memory cells 13 in the column of memory cells connected with the glowing stage 51 are ignited in a manner to be later described.

In time interval 119, following the time interval 118, the lead 73 sustaining voltage is applied to the cathode 16 of the stage 52 while the lead 72 sustaining voltage is still applied to the cathode of the stage 51. The gas plasma propagating through the opening 61 from the glowing stage 51 to the stage 52 ignites a discharge therein. For the reasons discussed above, gas discharges are not ignited in any of the higher numbered stages.

During time interval 120, following the time interval 119, the lead 72 voltage returns the cathode 15 to ground potential thereby extinguishing the glow in the stage 51. It is thus appreciated that by application of the leads 72-74 shifting signals that glow is transferred from the stage 51 to the stage 52 during the time interval 119. During the time interval 120, selected display memory cells 13 in the column of memory cells connected with the stage 52, are ignited in a manner to be described.

In a similar manner the three-phase leads 72-74 shifting voltages cause the glow discharge to transfer from stage to stage of the shifting register 11, the memory cells 13 associated with the single glowing stage being selectively ignited during the associated time interval. The time intervals illustrated in FIG. 2 during which glow is transferred from one stage to another are designated as T intervals and those intervals of FIG. 2 during which selected display cells 13 are ignited are designated as I intervals for convenience.

It will be appreciated that although the shifting register 11 is described with glow transferring from right to left for convenience of illustration, the glow may be transferred from left to right to the same effect.

It will furthermore be appreciated that the threephase glow shifting technique is generally known in the art of glow tube counting and shifting devices. The present invention, however, utilizes the novel barriers 27-34 between the stages of the shifting register 11 to create a serpentine path for the gas plasma propagation thereby decreasing the sensitivity of the device to variations in amplitude of the shifting signals from the source 70.

During the I intervals (FIG. 2) the display memory cells 13 are selectively ignited in a manner similar to that disclosed in said Ser. No. 90,538. The gas discharge sustaining potential is applied across the display cells 13 by the source 111. By suitable application of the addressing circuits 95 of positive and negative po-' tentials, selectively to the portion of the addressing anodes 80-82, a gas discharge column is extended through a selected channel in the column of apertures associated with the instantaneously glowing stage of the shifting register 11 to emerge from the selected aperture in the anode 82. Particles from the excited gas discharge column enter the associated one of the display cells 13 partially ionizing the gas therein and causing ignition thereof by the voltage applied by the source 111. The source 111 maintains the discharge in the selected cell after the discharge column has been extinguished by removing the addressing potentials. It is thus appreciated that the sustaining potential provided by the source 1 11 must be chosen intermediate the firing potential of the gas in the display cells when partially ionized by a gas discharge column from the addressing anodes and the firing potential of the gas when not so ionized.

The detailed operation of the display device 10 will now be explained in terms of selectively igniting a gas discharge in a display memory cell 121 connected with the stage 51 of the shifting register 11. During the time intervals when a glow discharge is present in the stage 51, gas discharge columns may be extended through the apertures of the matrix column connected therewith. With the potential from the source 111 applied as explained above, the addressing circuits 95 are activated to provide positive potentials to the portions 86, 88 and 90 of the addressing anodes -82 respectively, the portions 87, 89 and 91 thereof having negative potentials applied thereto. Under these conditions, gas discharge columns are extended through the four apertures in the portion 86 connected with the stage 51 and are inhibited from passage through the like apertures of the portion 87. Of the four discharge columns passing through the portion 86, only those two that are incident upon the portion 88 are transmitted therethrough. Those two columns incident upon the portion 89 are inhibited from further passage. In a similar manner, only that column passing through the portion 88 that is incident upon the portion 90 is transmitted therethrough, the column incident upon the portion 91 being inhibited from further passage. Thus a selected gas discharge column emerges from the aperture 122 of the anode 82 igniting the selected memory cell 121 in the manner previously described. It will be appreciated that by appropriate application of addressing potentials to the portions of the addressing anodes 80-82, any one of the display memory cells in the column of cells connected with the glowing stage 51 may be ignited. In a similar manner any one of the display memory cells in any other column may be ignited when the glow discharge is transferred into the associated stage of the shifting register 11. It is understood that application of positive addressing potentials to one portion of each of the addressing plates 80-82, respectively, uniquely addresses a row of the matrix of apertures, the particular aperture in the row being selected by the instantaneously glowing stage of the register 11. Once ignited, a pattern of lit cells will be maintained energized by the sustaining potential from the source 111 until erased by a momentary reduction or removal of this potential.

It will be appreciated that the amplitude of the positive potentials applied by the addressing circuits 95 to the respective addressing anodes 80-82 are selected in increasing fashion to correspond to the increasing distances of the respective anodes from the shifting register 11 in accordance with the-well-known gas discharge laws. The voltages must also be selected to preclude gas discharge breakdown between any of the electrodes 26 and 80-82 by choosing the amplitudes of the voltages associated therewith so that thedifference between any two of the voltages will be less than the sustaining potential of the gas. Breakdown must further be prevented between the cathode and any of the electrodes 14-22, 26 and 80-82. This is accomplished by the isolating resistor 112 that prevents significant current flow therebetween. In general, an electrical connection between the cathode 105 and the anode 26 is required to prevent the cathode 105 from floating to an arbitrary potential which could cause an undesirable breakdown between. the cathode 105 and theaddressing anodes 80-82.

It is further to be appreciated that the potentials provided by the addressing circuits 95 may be narrow pulses having durations sufficient to ignite the cells 13 which once ignited are so maintained by the source 111. It is further appreciated that the shifting register 11 may be activated only when a pattern of display cells to be ignited, the shifting register 11 being restarted whenever a new pattern is to be displayed. The register 11 is restarted by application of a starter pulse on the lead 71 when thesustaining potential is applied on the lead 72.

Although the display device 10 illustrated in FIG. 1 has been described in terms of utilizing the shifting register 11 for glow selection amongst the columns of the dot-matrix display and. the addressing anodes '80-82 for glow selection amongst the rows of the matrix, it is understood that the converse arrangement may be utilized to the same effect. Furthermore, although only eight information shifting register stages are illustrated in FIG. 1, it will beappreciated that any number of stages can be added to the register 11 without requiring additional shifting circuits or leads. It will further be appreciated that although the embodiment of the invention illustrated in FIG. 1 is explained in terms of shifting register cathode segments 14-22, the shifting register 11 may alternatively be constructed with anode segments and a common cathode plate. With such an arrangement, the construction of the barriers 27-34 and the member 38 would be accordingly altered.

A further alternative construction may be utilized where it is desired to reduce the amplitude of the starter pulse on the lead 71. A small cathode segment (not shown) that is maintained continuously ignited may be disposed adjacent the starter cathode l4 so that a starter pulse may be utilized with amplitude equal to the sustaining potential rather than equal to the ionization potential as described above.

Although as illustrated in FIG. 2 the shifting signals are returned to ground potential, it is appreciated that these voltages may be returned to a positive potential to further enhance the efficacious operation of the shifting register 11. It isfurther appreciated that the T intervals of FIG. 2 need only be long enough to transfer the glow from one stageto the next and the I intervals, which may be of unequal duration with respect to the T intervals, need only be long enough to light the points of the dot-matrix associated with the instantaneously glowing stage of the shifting register 11.

It is appreciated that because of the binary nature of the addressing scheme of the embodiment of the invention illustrated in FIG. 1, the addressing voltages may be readily controlled by a source of digital signals. Hence, patterns may be displayed by the memory cells 13 in accordance with signals provided by a digital computer thus rendering the invention particularly adaptable to providing computer controlled displays. The novel memory capability of the display cells 13 further enhance the adaptability of the display device 10 to this application as described in said Ser. No. 90,538.

In the display device described in said Ser. No. 90,538, 2" display cells are selectible by in addressing anodes and Zn electrical connections to them. In the present embodiment of the invention, for a square matrix array, one-half of this number of addressing anodes and connections are required since glow selection is effected along one display dimension by means of the gas discharge shifting register 11. Addressing anodes are then only required for glow selection in the other display dimension. The reduction in addressing anodes and connections by utilizing the present invention should be even more significant for a rectangular array. It is understood that the reduction in the required number of addressing anodes results in a concomitant reduction in the number of required insulating plates.

It will be appreciated that although the embodiment of the invention illustrated in FIGv 1 was described in terms of addressing anode plates having two binarily addressed electrically isolated portions, other arrangements of addressing anodes may also be utilized in practicing the invention. For example, addressing anodes each having more than two electrically isolated portions with a corresponding number of selection voltage connections to them may be employed where a further reduction in the number of addressing anodes plates is desired. Accordingly, a single addressing anode plate may also be utilized having an electrically isolated portion for each row of the matrix with a selection voltage connection to each portion. With this arrangement, although only one addressing anode plate is utilized, a substantially greater number of control leads is required compared to the binarily addressed configuration previously described for relatively large displays. This alternative arrangement may be desirable in small-scale displays having relatively small display matrices.

It will be appreciated that although the preferred embodiments of the invention illustrated in FIG. 1 was explained in terms of an 8 X 8 matrix of 64 apertures, matrices of tens or hundreds of thousands of apertures may be utilized in practical applications of the invention. Such large scale displays are rendered practical because of the significant power reduction effected by utilizing the present invention. Less power is required for the invention than for the prior art devices described above since only one stage of the shifting register 111 is ignited at any one time. Thus a large scale display will require a reasonable quantity of electrical power.

Additionally, rectangular as well as square matrices may be utilized. It is further appreciated that the scope of the invention is not limited to matrix configurations or to the particular pattern of portions of the addressing anodes as described above. Other patterns of apertures and addressing portions may be utilized to similar effect in practicing the invention.

It will be further appreciated that since no series resistors are utilized in the circuits of the display memory cells 13, voltage drops do not occur when a large number of cells are ignited thus preventing faulty cell ignition prevalent in devices requiring these resistors. Furthermore, it should be appreciated that although the display memory cells 13 are shown comprised of the cathode plate and the anode film 107, the display cells 13 may be individually constructed, each cell communicating with a channel of apertures through the addressing anodes 82.

The aforedescribed embodiment of the invention provides a twodimensional dot-matrix display where glow selection is effected in one display dimension by means of the glow shifting register 11 and in the other display dimension by means of the stack of addressing anodes 12. In this manner, the number of required addressing anodes and the required electrical power are reduced relative to the device disclosed in said Ser. No. 90,538. Another embodiment of the invention for providing these advantages as well as the other advantages supra is illustrated in FIG. 3. In this embodiment, each stage of the shifting register is of such size and shape as to connect with a two-dimensional array or submatrix of the total dot-matrix of display cells, each submatrix of cells being suitable for defining display symbols. For example, each register stage may for convenience connect with a respective 8 X 8 submatrix of 64 display cells in a dot-matrix display of tens or hundreds of thousands of display cells. This embodiment finds particular utility in alpha-numeric displays where each stage of the shifting register is the size of a display character. It will become apparent in the descriptions to follow that, for example, only six addressing anodes are required in an alpha-numeric display of unlimited capacity in which 64 dots are utilized for each character.

Referring now to FIG. 3, a display device 130 is depicted comprising gas discharge shifting register means 131, a stack of addressing anode electrode 132 and a plurality of gas discharge display memory cells 133. In a manner similar to that described with respect to FIG. 1, the shifting register means 131 is comprised of a plurality of cathode electrodes 134 and an anode electrode plate 135 spaced from the cathodes 134. A plurality of apertures are disposed through the anode plate 135 forming a matrix configuration of, for example, tens or hundreds of thousands of apertures. The cathodes 134 are disposed co-planarly with respect to each other and may be arranged in a variety of configurations to form shifting registers. For example, the cathodes 134 are illustrated arranged in rows 136, 137, 138 and 139 separated by electrically insulating wall members 143, 144 and 145 respectively. Each of the rows 136, 137, 138 and 139 may comprise an individual glow shifting register of the type described supra with respect fo FIG. 1. For example, the glow shifting register 136 comprises a starter stage 146 and information stages 147, 148, 149 and 150. The stages of the shifting register 136 are separated by baffle plates 151, respectively, having openings therethrough connecting the stages in the serpentine plasma propagation path previously described with respect to FIG. 1.

It is to be appreciated that a variety of arrangements for the stages of the shifting register means 131 may be utilized in practicing the instant embodiment of the invention. For example, the stages may comprise individual row shifting registers with individual starter stages as illustrated. Alternatively, the odd numbered rows may comprise a continuous shifting register having a starter stage where glow is shifted from left to right along the first row, from right to left along the third row, from left to right along the fifth row and so forth. Glow transfer paths (not shown) are required at the ends ofthe rows to propagate glow between the alternate rows. The even numbered rows of stages may similarly comprise a second shifting register having a second starter electrode. This arrangement may be utilized to prevent signal propagation between adjacent flow shifting rows. Another arrangement for the stages of the shifting register means 131 utilizing the odd and even numbered rows as separate shifting registers, respectively, is to employ a separate starter stage for each row and to apply common shifting signals to the alternate rows, respectively. With this arrangement, flow transference paths between the alternate rows of stages is not required.

It is appreciated from the foregoing that the stages of the shifting register means 131 may be configured in a wide variety of arrangementS Within the scope of the invention to suit the requirements of the display application for which the device is constructed. It will be further appreciated that the cathodes 134 and the respectively associated adjacent sections of the anode plate 135 together with the baffle plates 151 and the associated side wall members cooperate to form the stages of the shifting register means 131. In the embodiment of FIG. 1, the section of the register anode plate 26 associated with a stage of the register contained the apertures of a column of the dot-matrix. In the instant embodiment of FIG. 3, a section of the anode plate associated with a register stage contains the apertures of a two-dimensional submatrix of the total dot-matrix of apertures, for example the 8 X 8 submatrix of 64 apertures supra.

Electrical connections are made to the cathodes 134 via electrically conductive pins 152, respectively, which protrude from the rear of the structure in a manner similar to that described with respect to FIG. 1. The pins 152 are connected via leads 153 to a source of shifting signals 156. The electrical circuits from the source of shifting signals 156 to the shifting register means 131 are completed via a discharge stabilizing resistor 157 to the anode plate 135 which is connected to ground potential. The source of shifting signals 156 provides voltages similar to those illustrated in FIG. 2 for starting and transferring glow discharges from stage to stage of the shifting register means 131 in a manner similar to that described above and will not be repeated here for brevity.

As previously discussed, the stack of addressing anodes 132 is disposed adjacent the shifting register means 131. The stack of addressing anodes 132 is comprised of anode plates 160, 161, 162, 163, 164 and 165 each of which has a plurality of apertures therethrough forming a matrix configuration aligned with the apertures through the plate 135. interposed between the addressing anodes 160-165 are electrical insulators 170, 171, 172, 173 and 174, respectively, each having a matrix of apertures therethrough aligned with the apertures through the addressing anodes 160-165. Additionally, an apertured insulating plate 175 is interposed between the register anode 135 and the addressing electrode 160.

In a manner similar to that described above and in said Ser. No. 90,538, each of the addressing anodes 160-165 is comprised of two electrically conductive portions, electrically isolated from each other, one-half of the apertures being disposed through each of the portions, respectively. One of the portions of the addressing anode 160 contains one-half of the alternate quadruplets of adjacent columns of the matrix of apertures and the other portion contains the other half thereof. Similarly, one portion of the addressing anode 161 contains one-half of the alternate quadruplets of adjacent rows of the matrix of apertures and the other portion of the anode 161 contains the other half thereof.

The addressing anode plate 162 is also comprised of two portions, one portion containing one-half of the alternate pairs of adjacent columns of the matrix of apertures and the other portion containing the other half 

1. Gas discharge display apparatus comprising gas discharge shifting register means having a plurality of stages for propagating glow discharges from stage to stage thereof in response to shifting signals, a plurality of gas discharge display memory cell means, and a plurality of addressing electrode means interposed between said shifting register means and said display memory cell means and each having a plurality of apertures therethrough, said plurality of addressing electrode means being in superposed arrangement with respect to each other with said apertures aligned to form a plurality of gas conductive channels coupling said stages to said display memory cell means, said shifting register means, said plurality of addressing electrode means and said display memory cell means being in superposed arrangement with respect to each other, said plurality of addressing electrode means being connectible to a source of selectable addressing potentials generated in timed relation with respect to said shifting signals for selectively applying potentials to said electrode means to selectively extend gas discharge columns in said chaNnels from said glowing stages of said shifting register means to said display memory cell means for igniting gas discharges in selected display memory cell means.
 2. The apparatus of claim 1 in which said plurality of display memory cell means includes electrical conductor means for maintaining gas discharge sustaining potentials thereacross.
 3. The apparatus of claim 1 in which said plurality of channels connect respectively with said plurality of display memory cell means, and each said stage of said shifting register means connects with a plurality of said channels.
 4. The apparatus of claim 3 in which said plurality of addressing electrode means comprises a plurality of addressing plate means each comprising electrically conductive portions electrically isolated from each other, said apertures and portions being so arranged with respect to each other that with positive potentials applied to one said portion of each said plate means, gas discharge columns are extended from said glowing stages through selected channels associated with said one portion of each said plate means thereby igniting gas discharges in said display memory cell means associated therewith.
 5. The apparatus of claim 4 in which said portions and apertures are so arranged with respect to each other that with said positive potentials applied to one said portion of each said plate means at least one half of the gas discharge columns incident upon each said plate means are inhibited from passage therethrough until at least one said gas discharge column passes through a selected aperture in the last plate in said superposed arrangement of addressing plate means thereby igniting a gas discharge in said display memory cell means associated therewith.
 6. The apparatus of claim 5 in which said apertures are arranged in rows and columns forming a matrix configuration, said stages of said shifting register means being connected with said apertures comprising said columns of said matrix respectively, and said portions of said addressing plate means being so arranged with respect to said apertures comprising said rows of said matrix that with said positive potentials applied to one said portion of each said plate means at least one half of the gas discharge columns in a matrix column extended from the corresponding glowing stage of said shifting register means incident upon each said plate means are inhibited from passage therethrough until at least one said gas discharge column in said matrix column passes through an aperture in the last plate means in said superposed arrangement of addressing plate means thereby igniting a gas discharge in said display memory cell means associated therewith.
 7. The apparatus of claim 6 in which said apertures are arranged in groups each comprising a two-dimensional array of adjacent apertures suitable for defining display symbols, said stages of said shifting register means being connected with said apertures comprising said groups respectively, and said portions of said plate means being so arranged with respect to said apertures that with said positive potentials applied to one said portion of each said plate means at least one half of the gas discharge columns in a group extended from the corresponding glowing stage of said shifting register means incident upon each said plate means are inhibited from passage therethrough until at least one said gas discharge column in said group passes through an aperture in the last plate means of said superposed arrangement of addressing plate means thereby igniting a gas discharge in said display memory cell means associated therewith.
 8. The apparatus of claim 3 in which said shifting register means further includes baffle means separating said stages from one another and so constructed and arranged that gas plasma propagates freely from a lit stage to the next following stage and is impeded from propagating freely further to the stage following said next following stage.
 9. The apparatus of claim 8 in which each said stage comprises a gas discharge register cell, and said baffle means comprises a plurality of electrically insulating baffle plates between each register cell and the next following register cell, respectively, each said baffle plate having an opening therethrough connecting said each register cell with said next following register cell, adjacent baffle plates having said openings at opposite ends of said register cells, respectively.
 10. The apparatus of claim 9 further including a source of said shifting signals and in which said shifting register means comprises first register electrode means having a plurality of apertures therethrough connecting with said plurality of channels respectively, and second register electrode means spaced from said first register electrode means, one of said first and second register electrode means comprising a plurality of register electrodes separated from each other by said baffle plates, said first and second register electrode means and said baffle plates defining said register cells, said first and second register electrode means being adapted for connection therebetween of said source of shifting signals for propagating said glow discharges from said register cell to register cell in response to said shifting signals.
 11. The apparatus of claim 2 in which each said display memory cell means comprises first display electrode means having an aperture therethrough aligned with an associated one of said channels, and second display electrode means spaced from said first display electrode means, said first and second display electrode means being adapted for connection therebetween of a source of gas discharge sustaining potential.
 12. Gas discharge display apparatus comprising gas discharge shifting register means having a plurality of stages for propagating glow discharges from stage to stage thereof in response to shifting signals, a plurality of gas discharge display memory cell means, and electrode means interposed between said shifting register means and said display memory cell means and having a plurality of gas conductive channels therethrough extending from said stages to said display memory cell means, respectively, said shifting register means, said electrode means and said display memory cell means being in superposed arrangement with respect to each other, said electrode means being connectible to a source of addressing potentials generated in timed relation with respect to said shifting signals for applying potentials to said electrode means to extend gas discharge columns in said channels from said glowing stages of said shifting register means to said display memory cell means for igniting gas discharges in selectd display memory cell means associated therewith, respectively.
 13. The apparatus of claim 12 in which said electrode means comprises an electrically conductive plate having a plurality of apertures therethrough defining said plurality of channels respectively.
 14. The apparatus of claim 12 in which said plurality of display memory cell means includes electrical conductor means for maintaining gas discharge sustaining potentials thereacross.
 15. The apparatus of claim 14 in which each said display memory cell means comprises. first display electrode means having an aperture therethrough aligned with an associated one of comprises channels, and second display electrode means spaced from said first display electrode means, said first and second display electrode means being adapted for connection therebetween of a source of gas discharge sustaining potential.
 16. The apparatus of claim 12 further including a source of said shifting signals and in which said shifting register means comprises first register electrode means having a plurality of apertures therethrough connecting with said plurality of channels respectively, and second register elEctrode means spaced from said first register electrode means, one of said first and second register electrode means comprising a plurality of register electrodes each defining a stage of said shifting register means, said first and second register electrode means being adapted for connection therebetween of said source of shifting signals for propagating said glow discharges from stage to stage of said shifting register means in response to said shifting signals.
 17. Gas discharge display apparatus comprising gas discharge shifting register means having a plurality of stages for propagating glow discharges from stage to stage thereof in response to shifting signals, a plurality of memory means, and a plurality of addressing electrode means interposed between said shifting register means and said memory means and each having a plurality of apertures therethrough, said plurality of addressing electrode means being in superposed arrangement with respect to each other with said apertures aligned to form a plurality of gas conductive channels coupling said stages to said memory means, said shifting register means, said plurality of addressing electrode means and said memory means being in superposed arrangement with respect to each other, said electrode means being connectible to a source of selectrable addressing potentials generated in timed relation with respect to said shifting signals for selectively applying potentials to said electrode means to selectively extend gas discharge columns in said channels from said glowing stages of said shifting register means to said memory means for activating selected memory means.
 18. The apparatus of claim 17 in which said memory means comprises gas discharge display memory cell means respectively.
 19. The apparatus of claim 1 in which said shifting signals comprise pulses of d.c. sustaining potential.
 20. The apparatus of claim 12 in which said shifting signals comprise pulses of d.c. sustaining potential.
 21. The apparatus of claim 17 in which said shifting signals comprise pulses of d.c. sustaining potential. 